hwmon: (max6650) Switch to using the new API kobj_to_dev()

Switch to using the new API kobj_to_dev() to fix the below warnning:
drivers/hwmon/max6650.c:324:60-61: WARNING opportunity for
kobj_to_dev().
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Link: https://lore.kernel.org/r/1609376621-46463-1-git-send-email-tiantao6@hisilicon.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/max6650.c

@@ -321,7 +321,7 @@ static SENSOR_DEVICE_ATTR_RO(gpio2_alarm, alarm, MAX6650_ALRM_GPIO2);
 static umode_t max6650_attrs_visible(struct kobject *kobj, struct attribute *a,
 				     int n)
 {
-	struct device *dev = container_of(kobj, struct device, kobj);
+	struct device *dev = kobj_to_dev(kobj);
 	struct max6650_data *data = dev_get_drvdata(dev);
 	struct device_attribute *devattr;